Coupling light from high power light sources, such as lasers, into optical fibers has become increasingly useful in many applications, including for example, optical communication, materials processing, medicine, and military applications.
Optical fiber typically is comprised of a central core, a cladding layer surrounding the core, and a buffer layer that surrounds and protects the cladding. When light is properly coupled into optical fiber it is directed into the core, which with the cladding is designed to contain and guide the light along the length of the fiber. However, coupling from high energy sources of light is rarely perfect and some optical energy may stray into the cladding, the buffer layer, and/or the surrounding environment. This errant high power light can heat the optical fiber and/or surroundings to the point that there is significant damage and/or destruction within the system. In particular, it is well known that errant high power light can damage the buffer layer of an optical fiber. As a result, it is common to strip the buffer layer from the input end of an optical fiber before mounting it.
However, even with the buffer layer partially removed, if the high power light directed to the input core of the optical fiber is misaligned then at least a portion of the light may 1) enter the fiber cladding, 2) illuminate the fiber holder, and/or 3) reflect back to the source. In each case, this errant high power can cause catastrophic damage to the fiber and/or laser module, or collateral damage to other components located nearby the fiber. For example, stray energy that is coupled into the cladding may propagate and cause damage to the buffer layer further along the optical fiber and/or to the adhesive used to secure the optical fiber to the mount.
In view of the foregoing, it may be understood that there are significant problems and shortcomings associated with current solutions and technologies for coupling high power light into an optical fiber.